Electrical heating apparatus



March 28, 3950 F. T. GRoTHOUsE 2,502,147

'ELECTRICAL HEATING APPARATUS Filed April 5, 1949 2 Sheets-Sheet 1 Fissi. fr

FIL LED WITH /MSULA TMG CMPOl//YD Inventor: F-Tamk T. GT-othoue,

b5 l--lis Attorney.

March 28, 1950 F. T. GRo'rHousE 2,502,147

ELECTRICAL HEATING APPARATUS Filed April 5, 1949 2 Sheets-Sheet 2 Ihverwtor': Fran k T. (3T-ot house,

Patented Mar. 28, 1950 ELECTRICAL HEATING APPARATUS Frank T. Grothouse, South Euclid, Ohio, assigner to General Electric Company, a corporation of New York Application April 5, 1949, Serial N0. 85,661

Claims.

This invention relates to electrical heating apn paratus of the panel type and more particularly to improvements in such apparatus having a plun rality of heating panels mounted on a surface, to improvements in the construction of the individual panels, and to an improved arrangement for supplying power to each panel.

In the art of heating enclosures, an animate body within the enclosed space will have a feel-- ing of warmth if the enclosed space is heated by large radiating areas, even though the temperatrle within such enclosure is relatively low.

t has been found also that less total heat .is required for a givenenclosed space to impart a feeling of comfort when large heated areas ernn ployed within the enclosure, rather than radia-A tors of the conventional type having a relatively small surface heated to a higher temperature. The explanation of this phenomenon appears to be that by employing large heating surfaces, ta@ rate of heat radiation from the body to the surrounding surfaces is reduced. It is therefore a primary object of my invention to provide elec-- trical apparatus for heating large areas or surfaces within an enclosure.

Electrical panel heating apparatus should provide versatility so that the heating elements may be applied to the walls, ceiling, or floor of any enclosed space. Furthermore, since such a heating system will often be placed in a house or building having human occupants, the appearance of the installation should be pleasing. From the standpoint of safety for the occupants, the electrical heating panels must of necessity provide adequate protection from electrical shock or burns. Also, it is highly desirable that the panels comprising the apparatus be resistant to moisture and physical shook to avoid expensive maintenance. Furthermore, it is important that the panel type heaters have a low thermal mass, so that upon change in heating reqiurements, the electrical power supplied to the panels can be varied to produce an immediate change in the amount of heat radiated by such panels. Also, in order to be competitive with conven tional heating equipment now employed, the cost of producing such heating apparatus must be reduced to a minimum. It is therefore a further object of my invention to provide apparatus for heating an enclosure fullling the above requirements by providing tile-shaped panels, which are thin and have a low thermal mass, and which are adequately protected electrically and physin cally. it is another object of my invention to provide for the supply of electric power to each 2 tile-shaped panel, so that all thel panels are connected in parallel with the power source.

Another object of my invention is to provide a panel construction and means for supplying electrical power thereto for installation on an existing surface with but minor modifications. Still a further object is to provide a heating panel construction with the power supply means lecated in concealed conduits; and to provide a conduit or raceway construction for the power supply lines which may have substantially the same thickness as the heating panels to result in an installation of pleasing appearance.

For fulfillment of the foregoing objects, an important feature of my invention consists in providing an improved electrical heating panel having a heating element mounted within a shallow pan-shaped housing, the housing protecting the electrical heating element and providing a means by which the panel may be mounted on a surface. A further important aspect ofthe invention consists of an improved arrangement for supplying electrical power to a plurality of panels by connectors quickly engageable with terminals on each panel heating element and with terminals on the electrical supply line.

The features of my invention which I believe to be novel are set forth with particularty in theappended claims. My invention itself however, together with further objects and advanM tages thereof, may best be understood by referu ence to the following description taken in connection with the accompanying drawings, in which Fig. l illustrates a portion of a room with electrical heating apparatus, in accordance with my invention, installed on a Wall of the room; Fig. 2 is an enlarged sectional View taken along the line '2-2 of Fig. l; Fig. 3 is enlarged cut-- away View of a portion of the installation shown by Fig. l; Fig. e is an exploded perspective view of the components of an electrical heating panel in accordance with my invention; Fig.A 5 illustrates anl alternative embodiment of the heatlng element; and Fig. 6 is a partial cross-sectional view of thev heating element shown by Fig. 5.

Electrical heating apparatus in accordance with my invention is suitable for installation on any substantially flat surface. For example, a typical installation is shown in Fig. l, with this heating apparatus, in the' form oi panels l and may be made in a variety of sizes in order to provide flexibility, permitting installation within any existing building structure. For example, the relatively long narrow rectangular panels E may be employed for covering larger unobstructed surfaces on a wall; and the smaller square blocks or tiles 3 may be employed to iill in smaller spaces, such as around window A. The electrical supply line for the installed panels is concealed within a conduit or raceway 5, which may be mounted as in Fig. l, to blend with a baseboard 6.

To protect adequately the heating element, and to support each panel, a shallow pan-shaped housing l is employed, as best shown by Fig. 4. Preferably, the panel housing is made from sheet metal, such as sheet steel or anodized aluminum, although other thermally conductive material may be suitable. This housing may be manufactured by any suitable process, and as here shown it is formed by simple cutting and bending operations. Housing 'l thus provides an enclosure for the heating element of the panel dened by a panel surface portion 8 and narrow upstanding walls 9. As a means for mounting the panel on surface I, such as shown by Fig. 2, outwardly extending lateral flanges Ill are provided on each of the housing wall portions 9.

The heating element for each panel, in accordance with one form of my invention, is made up as a separate unit l2 receivable within the shallow pan-shaped housing 7. As shown by Figs. 2 through 5, the electrical resistance element II is in the form of a woven fabric. A number of different methods exist for preparing such a fabric heating element. For example, resistance wire may be woven into a piece of cloth; or strands of insulating bre or threads may be used for the weft of the element II, with resistance wires of Nichrome, nickel, or other resistance material, constituting the warp of the fabric. The completed fabric is impregnated with a suitable insulating compound, such as a phenolic resin, to insulate electrically the resistance wires from one another, and to fireproof the fabric.

The connection of electrical power to each heating element is facilitated by employing terminal buses I3 and I4 attached along two opposite edges of resistance element II. Each terminal bus is fabricated from a at strip of copper, or other electrical conducting material, folded over on itself to form a U-shape. An edge of the resistant element I I is placed between the legs of this U-shaped bus and rivets are applied to anchor the resistance element to each terminal bus. By cutting away a small part of the closed edge at the end of each terminal bus, bifurcated portions Iii and IG are provided for cooperation with panel connectors 2i.

Because of the somewhat delicate nature of the fabric type heating element, and the danger of breaking the electrical resistant wires during in stallation of the heating element in the panel housing, it is preferred to mount this heating element on a backing II. This backing should be of insulating material. such as heavy insulating paper, so that in addition to providing a substantially rigid support for the heating element II, it also serves as an insulating means between the conductors of the heating element I I and the panel housing 'I. To mount heating element II on backing II, the terminal buses I3 and I I are first riveted to terminal bus anchors I8 and I9 (Fig. 3). Terminal bus anchors I8 and I9 are then riveted to the insulating board or backing I'I, thus supporting the heating element I I in this backing. By making the terminal bus anchors I8 and I9 of an insulating material, such as a molded phenolic condensation product, an insulating barrier is established between the terminal buses I3 and I4 and the side walls 9 of the panel housing. To insure efficient heat transfer from the heating element II through the insulating backing I'I and the panel surface 8, it is desirable that the heating element be held in intimate contact with the insulating backing I'I. Therefore, upon completion of the mounting of the heating element I I, I prefer to employ a cement to maintain the resistance element II in contact with the backing Il. The invention is not limited to the use of cement for this purpose, but obviously clamping ears, or clamping strips of insulating material might be employed to maintain heating element II in contact with insulating backing I'I.

Important aspects of this invention are the ease with which the heating element assembly I2 may be mounted within the pan-shaped housing, the improved method for mounting the assembled panels on a surface, and the provision for a quick connection from the power source to each panel. As best shown in Fig. 4, for providing connection from the power supply source to the heating element, rectangular apertures 2l) are provided in the narrow side walls u of the panel housing. These apertures 20 are oriented in panel housing 'I so that when the heating element assembly I2 is placed in position within the housing, the apertures 221 are adjacent bifurcated ends I5 and I6 of the terminal buses I3 and I4.

To establish the electrical connection between the power supply source and the heating element of the panel, or to connect the heating elements of adjacent panels together, connectors 2I are employed. Conductor bar 22 of connector 2l consists of a copper conductor bar of substantially rectangular cross-section, with its ends exposed to make contact with the bifurcated ends I5 and I5 on each terminal bus. An inner insulating sleeve 23 encloses the conductor bar 22 to insulate it from the panel housing 'I when the connector 2I is in position. An outer insulating sleeve 24 is provided on connector ZI,l

and this sleeve serves as a spacer to properly position the connector when it is in place between adjacent panels. Thus, to assemble the heating element assembly I2 within panel housing 'I, it is merely necessary to place assembly I2 within the shallow pan-shaped housing, and by insertion of connectors 2I through apertures 20, assembly I2 is held in position upon engagement of conductor bars 22 with the bifurcated ends I5 and I6.

When the heating element assembly Il! has been mounted within panel housing 1, the panel is ready for installation on the wall surface I. For attaching these panels to the surface, a nailing clamp 25 (Figs. 2 and 3) is employed wherever the corners of two or more panels meet. The first step in mounting of the panels to place two adjacent panels on the surface I with adjacent edges of the panel surface portions B contiguous to one another. Nailing clamp 25, which is in the form of a rectangular plate, is then pla-ced over the corners of laterally extending flanges I0 on the backside of the panels. A nail 26 or other fastener is driven through the nailing clamp 25 to fasten adjacent corners of flanges I0 against the surface on which the panels are mounted. In cases where the corners of four panels meet in a point, the first two panels are clamped to the surface as described above. The third and fourth panels are then mounted by driving the corners of their respective flanges Il) underneath nailing clamp 25.

It will be noted that in connection with each panel housing, the outside edges of outwardly eX- tending anges lll lie within the perimeter of panel surface portion 8. The purpose of this is to provide for a completed installation in which gaps between the edges of adjacent panels are eliminated. Thus the edges of panel surface portion `8 for each panel may always be in contiguous relation with the corresponding edges of adjacent panels.

Power supply lines 2'.' and 2B are concealed in raceway 5 extending along one edge of the completed panel installation, as Shown by Fig. 1. The details of this raceway or conduit constructio-n are best seen in Fgs. 2 and 3. The incoming power supply lines 2l and 28 are held in position at their point of entry into raceway 5 by suitable bushing and packing gland 29. Body portion 30 of the raceway is in the form of a channel with laterally extending anges 3i and 32 extending outwardly from the open side of the channel, and it is lined with a suitable insulating paper or fabric 33. A raceway cover 34 lined with insulation 35 is attachable to body portion 30, so that upon completion of the electrical connections to the power supply line the cover may be placed in position; and if for any reason, such as for inspection or repair, it is desirable to remove conduit cover 3A it may be easily removed and later snapped back in position. To maintain cover 34 in position, the lower edge of the cover, as shown in Fig. 2, is provided with a bent over flange 36 receivable underneath fiange portion 32 of the raceway body 30; and slightly offset flange 3l is provided along the upper edge of cover 34 for engagement underneath the panel surface portions 8 of the adjacent row of panels. A barrier 38 may be employed to completely isolate the electrical supply lines and connections within the raceway. This barrier, preferably, is welded in position to raceway body 30, and spaced apertures are provided through barrier 38 for con nectors 2l.

The mounting of raceway 5 and establishment of connections to the adjacent row of panels 3 is performed in accordance with this construction as follows. Body portion 33 is installed within a recess cut out from wall l, with flanges 3| and 32 resting against wall l. Nailing clamp 25 may next be positioned overlying the flange 3| on the raceway body and the nail 26 is driven in to clamp the body 30 in position. Panel connectors 2| are then inserted through the `apertures provided in barrier plate 38, the spacing of these connectors corresponding to apertures 25 in the adjacent row of panels, so that the connectors are in proper alignment for ready connection to the panel heating elements. Connections are next established with the power supply lines 2 l and 28 by employing connector clamps 39 which may be folded around a conductor and clamped to one end 22 of a connector 2| by a bolt lo having a lock washer 4ta. The invention is not limited to this particular type of connector clamp, of course, for obviously other types of clamps may be employed. However, in order to use standardized parts, it is preferable to employ connector clamps of such a type that the same type of connector 2l may be outside the legs of the connector clamp 39 and a screw All again holds connector end portion 22 in rm contact with the clamp. An obvious modification is to cross conductors 21 and 28 between the connectors so that all connector clamps are assembled uniformly. Thus even though conductors 21 and 28 lie in the same plane with one conductor above the other, identical connecting clamps and connectors may be used in both instances.

At this stage of the installation, assembled panels 3 may be mounted in position by driving the flanges l0 of the panel housings underneath the corners of nailing clamp 25, a nailing clamp 25 being employed at each point along the raceway where two panels come together. While the adjacent row of panels are thus being mounted, the other ends of the connectors 2| are inserted through apertures 20 in the panel housings to engage bifurcated ends l5 and i5 of the electrical heating elements. Finally raceway cover 34 is placed in position by engaging flange 31 under the edges of panel surface portions 8, and engaging flange 36 of the cover under ange 32 of raceway body 30.

The next step toward the completed installation is to mount and connect the upper rows of panels. Nailing clamps 25 are nailed in position at the upper corners of flanges Il! of the lower rovv of panels 3. The connectors 2| between the lower row of panels and the next adjacent row above the lower row are placed in position. Then each panel is placed in alignment with a lower panel and its flange i il is driven underneath nailing clamp 25, simultaneously inserting connectors 2i through apertures 2Q, so that as the upper panel is driven into position, the electrical connection is established between the connector ends and bifurcated portions l5 and l5. This same process is repeated until the uppermost row of panels has been installed, and the top of the uppermost panel may be held against the wall by merely driving a nail or other fastener through its flange I0.

As a. further precautionary measure to prevent danger of lire, and to insure that the electrical heating element will be insulated from wall l, the wall l may be covered with impregnated paper or fabric 4|. In addition the backside of each panel assembly may be filled with an insulating compound to ll up the space 42. This insulation not only insulates electrically, but also reduces the heat loss through wall l The installation is finally completed by providing an appropriate finish for the panel surfaces 8, and by placing ller blocks in the recesses of all panel edges where no adjacent panels are installed. The surface finish may of course be paper, paint, tapestry, or any other suitable material which results in a finished appearance for the walls. It is to be understood, however, that my invention is not limited to an installation with such nishing of the panels.

While this installation has been particularly described with respect to a wall-surface, it will be understood that the same methods and the same elements may be employed for ceiling installation; likewise 'the same type installation is suitable for the floor of a building structure, in which case panel surfaces 3 may be covered with linoleum or carpet. Since the enclosure, in accordance with this invention, is heated by such large warm areas, the temperature of the panel surfaces need be only slightly above the desired room temperature. I'hus there is no fire danger in employing conventional wall, ceiling, or floor coverings over the panels.

In Figs. 5 and 6, I have shown an alternative type of heating element which may be used with this Iheating panel construction in place of woven fabric heating element il. This heating element is made by cementing or gluing a layer of metallic foil 44 over an insulating backing 43. A suitable cutter or stamping machine is employed to cut V-shaped notches #la through the metallic foil 44 and partially through the insulating backing 43. The foil is thus severed alternately from opposite edges to form the legs of a grid, resulting in a resistor having a serpentine path for the passage of the electrical. current. This heating element may then be mounted in exactly the same fashion as fabric element l l shown by Fig. 4; that is, terminal buses i3 and I4 are folded about edges it and fil of the heating element shown by Fig. 5, and these terminal buses are affixed to terminal bus anchors such as I8 and I9 shown by Fig. 4. rlhe 'terminal bus anchors are in turn mounted on an insulating backing such as l1. In mounting this foil grid however, it is preferable to have the foil side facing inwardly toward the backside of the panel surface portion 3 in order that the maximum amount of heat from this heating grid will be radiated from the panel.

While I have shown particular embodiments of the various phases of my invention, it will be understood, of course, that I do not wish to be limited thereto, since modifications may be made and I, therefore, contemplate by the appended claims to cover any such modiiicatidns as fall within the true spirit and scope of my invention,

What I claim as new and desire to secure by Letters Patent of the United States is:

l. An electrical heater of the panel type com-- prising a heating element having terminals thereon, a shallow pan-shaped housing for said element, said housing having apertures located adjacent said terminals, means for supporting and insulating said element within said housing, and connectors for supplying power to said element extending through said apertures to engage said terminals.

2. In electric heating apparatus of the type having a plurality of panels affixed to a surface, a panel housing and heating element assembly comprising a shallow pan-shaped housing having an imperforate face and an open back, an electrically insulated heating element receivable within said housing through said open back, means for attaching said housing back against the surface, and means for supplying power to said heating element.

3. An electrical heater of the panel type comprising a heating element with te "minals thereon, a housing for said element having a panel surface portion and narrow side wall portions extending away from said surface portion, means for supporting and insulating said element within said housing, said housing having apertures in said wall portions adjacent said terminals, and connectors engageable with said terminals and extending outside said housing through said aper-j tures, said wall portions having outwardly extending flanges for mounting said housing on a surface.

4. Electrical heating apparatus of the panel type comprising a housing for each panel, said housing having a panel surface portion and narrow wall portions extending away from said panel surface portion, outwardly extending flanges on each of said wall portions, the outer edges of said flanges being within the perimeter oi said panel surface portion whereby said housings may be attached to a surface by means including said flanges with the edges of said surface portion of each panel contiguous with corresponding edges of adjacent panels, a heating element for each panel, a terminal bus connected to and extending along one edge and a second terminal bus connected to and extending along an opposite edge of said heating element for supplying power thereto, each terminal bus having bifurcated ends for quick connection to a power supply source, said' narrow wall portions having apertures adjacent said bifurcated ends, insulating means upon which said heating element is mounted within said housing, and panel connectors insertable through said apertures to frictionally engage said bifurcated ends.

5. An assembly of heating panels for mounting on a surface comprising a plurality of attaching plates, means fastening said plates to the surface, and a plurality of heating panels of rectangular configuration, each panel including outwardly extending flanges adapted to be positioned between said plates and the surface for retaining said panels in position on the surface.

6. In electrical heating apparatus of the panel type having a plurality of panels affixed to a surface and a heating element with terminals thereon positioned in each panel, a housing for each panel for enclosing said heating element comprising a panel surface portion, narrow wall portions extending away from said panel surface portion, flanges extending outwardly from said narrow wall portions with the outer edges of said flanges within the perimeter of said panel surface portion, and means cooperable with said flanges for aflixing said housing to a surface, whereby the edges of said panel surface portion of each panel are contiguous with corresponding edges of adjacent aiiixed panel housings.

'7. In an electrical heating panel, a heating element comprising an electrical resistor, a terminal bus attached to and extending along one edge of said resistor and a second terminal bus attached to and extending along a second edge of said resistor, each terminal bus having bifurcated terminals on its ends, an insulating sheet substantially coextensive with said resistor and said attached buses, and means for afhxing said resistor and said buses to said insulating sheet.

8. Electrical heating apparatus of the type having a plurality of panels of low heat mass attached to a surface comprising a shallow pan-shaped housing of rectangular configuration for each panel, an insulated heating element within each housing, said heating element having terminals adjacent each corner, said housing having apertures adjacent each terminal, connectors engageable with corresponding terminals of adjacent panels and extending through said apertures, and means for attaching said housings to the surface.

9. Electrical heating apparatus of the type having a plurality of panels of low heat mass attached to a surface comprising a shallow panshaped housing of rectangular congur'ation'or,

each panel, an insulated heating element within each housing, said heating element having-,bifurcated terminals adjacent each corner, saidhbusing having apertures adjacent each terminal, bar connectors with an intermediate insulated portion and end contact portions engageable with corresponding terminals of adjacent panels and extending through said apertures, and means for attaching said housings to the surface with edges along the exposed face of each panel in contiguous relation with corresponding adjacent panel edges.

l0. Electrical heating apparatus of the type having a plurality of panels of low heat mass attached to a surface comprising a shav w panshaped housing of rectangular conl'giraton for each panel` an insulated heating element within cach housing, said heating element minals adjacent each corner, said ho ng having apertures adjacent each terminal, connectors engageable with corresponding terminals of adjal0 cent panels and extendingthrough said apertures, means for attaching said housings to the surface, and a conduit with electrical power supply lines therein and having apertures adjacent each connector, said connectors form panels adjacent said conduit extending into said conduit and connecting to said power lines.

FRANK T. GROTHOUSE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Country Date Great Britain Dec. 20, 1934 Number Number 

